1. Field of the Invention
The present invention is related to media control and, more specifically, media control valves used to control the flow of a media into a fluid stream as part of an apparatus for treatment of a surface.
2. Description of the Related Art
A typical media control valve is disclosed in U.S. Pat. No. 3,476,440 (xe2x80x9cthe ""440 patentxe2x80x9d), which is hereby incorporated by reference in its entirety. The valve of the ""440 patent is attached to a media vessel and controls the flow of the media from the media vessel into a conduit containing a fluid stream. This conduit terminates in a nozzle. Fluid and media pass through the nozzle at high speed and are typically used to treat surfaces.
Other uses for media control valves have been proposed. For example, U.S. Pat. No. 5,810,045 (xe2x80x9cthe ""045 patentxe2x80x9d) discloses a valve for introducing particulate materials into a high-pressure air stream and suggests several uses for this valve. For example, the ""045 patent suggests that the valve may be used for purposes such as introducing fluid catalytic cracking catalyst particles into fluid catalytic cracking units used to crack and reform various petroleum based products, introducing particulate catalysts into other kinds of chemical processes and spraying particulate ingredients on adhesive substrates as part of various manufacturing processes.
Various improvements to the basic media control valve have been proposed. For example, U.S. Pat. No. 5,407,379 (xe2x80x9cthe ""379 patentxe2x80x9d) and U.S. Pat. No. 5,401,205 (xe2x80x9cthe ""205 patentxe2x80x9d) disclose a media control valve having a media passage between the media control valve and the conduit. The media passage converges into a slot-shaped outlet in the conduit so as to reduce the perimeter of the outlet placed perpendicular to air flow and consequently reduce turbulence as air passes across the outlet. The media control valve disclosed in the ""205 and ""379 patents is particularly useful in metering and dispensing sodium bicarbonate media.
The ""045 patent, discussed previously, also discloses a modification of the original media control valve, including the use of multiple seals around a plunger of the valve with an exhaust therebetween to remove any contaminants that breach the seals.
According to one embodiment of the present invention, a media control valve is provided including a valve body having a media inlet and a media outlet, and a plunger and sleeve positioned within the valve body. The media control valve also includes a media opening in the sleeve having a first portion proximate to the media outlet and a second portion distal to the media outlet, wherein the second portion is broader than the first portion. The media control valve further includes a housing connected to the valve body, a piston positioned within the housing and connected to the plunger, and a base connected to the valve body in communication with the media outlet.
According to another embodiment of the present invention, a valve is provided including a body having an opening and an outlet. The opening in the outlet includes a first portion proximate to the outlet and a second portion distal to the outlet, wherein the second portion is broader than the first portion. The valve further includes a closing member positioned within the body so as to selectively cover the opening.
According to another embodiment of the present invention, a valve is provided including a body and a closing member positioned within the body. The valve also includes a housing and a piston within the housing. The piston is connected to the closing member and has a contaminant isolation region.
According to another embodiment of the present invention, a media control valve is provided including a valve body having a media inlet and a media outlet, and a plunger and sleeve positioned within the valve body. The media control valve also includes a media opening in the sleeve, a housing connected to the valve body, a piston having a contaminant isolation region positioned within the housing and connected to the plunger and a base connected to the valve body in communication with the media outlet.